I’m not sure if it’s just my computer, I don’t have another one to test.
I tried it on both my laptop’s built in keyboard and a USB one, and the results seems to be same.
Pressing two keys in close succession after the other causes the latter one to register twice after a brief period if the latter key is held down.
Specifically in my linked example.
Pressing the L key will make a sound.
I hit space, let go of space immediately, then press and hold L.
It’ll beep once, then again after a second.
This will happen with other keys from what I can see.
This won’t happen if the first key is held down, but after some further testing I’ve seen that if you do hold down Space and L, it’ll beep after hitting L, then it’ll beep again after letting go of Space, if you’re still holding L.
This does not seem to happen on browser.
I juuuust now made an executable, and the behavior seems to be same there.
Here is the browser version, the included download is the project file and assets.